Implement optional module loading

The syntax is:

using? cli

Now each module use results in two bool variables: <module>.loaded and
<module>.configured.

Also implement variable visibility (the above two variables are limited
to project).

2 files changed, 19 insertions, 13 deletions

diff --git a/build/bin/module b/build/bin/module
index b87a0b0..5dd720f 100644
--- a/build/bin/module
+++ b/build/bin/module
@@ -6,14 +6,17 @@
 #define BUILD_BIN_MODULE
 
 #include <build/types>
+#include <build/utility>
+
 #include <build/module>
 
 namespace build
 {
   namespace bin
   {
-    extern "C" void
-    bin_init (scope&, scope&, const location&, std::unique_ptr<module>&, bool);
+    extern "C" bool
+    bin_init (
+      scope&, scope&, const location&, unique_ptr<module>&, bool, bool);
   }
 }
 
diff --git a/build/bin/module.cxx b/build/bin/module.cxx
index 25700c6..c7da647 100644
--- a/build/bin/module.cxx
+++ b/build/bin/module.cxx
@@ -29,12 +29,13 @@ namespace build
     static const strings liba_lib {"static"};
     static const strings libso_lib {"shared"};
 
-    extern "C" void
+    extern "C" bool
     bin_init (scope& r,
               scope& b,
               const location&,
               std::unique_ptr<module>&,
-              bool first)
+              bool first,
+              bool)
     {
       tracer trace ("bin::init");
       level5 ([&]{trace << "for " << b.out_path ();});
@@ -81,15 +82,15 @@ namespace build
       //
       if (first)
       {
-        variable_pool.find ("config.bin.lib", string_type);
-        variable_pool.find ("config.bin.exe.lib", strings_type);
-        variable_pool.find ("config.bin.liba.lib", strings_type);
-        variable_pool.find ("config.bin.libso.lib", strings_type);
-
-        variable_pool.find ("bin.lib", string_type);
-        variable_pool.find ("bin.exe.lib", strings_type);
-        variable_pool.find ("bin.liba.lib", strings_type);
-        variable_pool.find ("bin.libso.lib", strings_type);
+        var_pool.find ("config.bin.lib", string_type);
+        var_pool.find ("config.bin.exe.lib", strings_type);
+        var_pool.find ("config.bin.liba.lib", strings_type);
+        var_pool.find ("config.bin.libso.lib", strings_type);
+
+        var_pool.find ("bin.lib", string_type);
+        var_pool.find ("bin.exe.lib", strings_type);
+        var_pool.find ("bin.liba.lib", strings_type);
+        var_pool.find ("bin.libso.lib", strings_type);
       }
 
       // Configure.
@@ -164,6 +165,8 @@ namespace build
 
       install::path<liba> (b, dir_path ("lib"));  // Install into install.lib.
       install::mode<liba> (b, "644");
+
+      return true;
     }
   }
 }